public ActionResult ThongBao(string noiDungThongBao, string nguoiNhan, FormCollection form)
        {
            if (nguoiNhan != null)
            {
                UserModel um = new UserModel();
                AccountDAL adal = new AccountDAL();

                int IDSender = adal.getIDFromUsername(User.Identity.Name);
                int IDReciver = adal.getIDFromUsername(nguoiNhan);
                um.SendMessage(IDSender, IDReciver, noiDungThongBao);

                return RedirectToAction("Index", "Home");
            }
            else
            {
                GlobalDataModel gdm = new GlobalDataModel();
                gdm.ThemThongBao(noiDungThongBao);
                return RedirectToAction("Index", "Home");
            }
            return null;
        }